Before making changes, it's a good idea to explore the work already
done by others. Perhaps the new feature or improvement you're looking
for is available in another plug-in already? If you find a bug,
perhaps someone else has already fixed it?

To answer these questions and more, take a moment to explore the
overall Bazaar Platform. Here are some links to browse:

There is a very active community around Bazaar. Mostly we meet on IRC
(#bzr on irc.freenode.net) and on the mailing list. To join the Bazaar
community, see http://bazaar-vcs.org/BzrSupport.

If you are planning to make a change, it's a very good idea to mention it
on the IRC channel and/or on the mailing list. There are many advantages
to involving the community before you spend much time on a change.
These include:

you get to build on the wisdom on others, saving time

if others can direct you to similar code, it minimises the work to be done

it assists everyone in coordinating direction, priorities and effort.

In summary, maximising the input from others typically minimises the
total effort required to get your changes merged. The community is
friendly, helpful and always keen to welcome newcomers.

If you'd like to propose a change, please post to the
bazaar@lists.canonical.com list with a bundle, patch, or link to a
branch. Put '[PATCH]' or '[MERGE]' in the subject so Bundle Buggy
can pick it out, and explain the change in the email message text.
Remember to update the NEWS file as part of your change if it makes any
changes visible to users or plugin developers. Please include a diff
against mainline if you're giving a link to a branch.

You can generate a bundle like this:

bzr bundle > mybundle.patch

A .patch extension is recommended instead of .bundle as many mail clients
will send the latter as a binary file. If a bundle would be too long or your
mailer mangles whitespace (e.g. implicitly converts Unix newlines to DOS
newlines), use the merge-directive command instead like this:

Please do NOT put [PATCH] or [MERGE] in the subject line if you don't
want it to be merged. If you want comments from developers rather than
to be merged, you can put '[RFC]' in the subject line.

Anyone is welcome to review code. There are broadly three gates for
code to get in:

Doesn't reduce test coverage: if it adds new methods or commands,
there should be tests for them. There is a good test framework
and plenty of examples to crib from, but if you are having trouble
working out how to test something feel free to post a draft patch
and ask for help.

Doesn't reduce design clarity, such as by entangling objects
we're trying to separate. This is mostly something the more
experienced reviewers need to help check.

Improves bugs, features, speed, or code simplicity.

Code that goes in should pass all three. The core developers take care
to keep the code quality high and understandable while recognising that
perfect is sometimes the enemy of good. (It is easy for reviews to make
people notice other things which should be fixed but those things should
not hold up the original fix being accepted. New things can easily be
recorded in the Bug Tracker instead.)

Anyone can "vote" on the mailing list. Core developers can also vote using
Bundle Buggy. Here are the voting codes and their explanations.

If a change gets two approvals from core reviewers, and no rejections,
then it's OK to come in. Any of the core developers can bring it into the
bzr.dev trunk and backport it to maintenance branches if required. The
Release Manager will merge the change into the branch for a pending
release, if any. As a guideline, core developers usually merge their own
changes and volunteer to merge other contributions if they were the second
reviewer to agree to a change.

To track the progress of proposed changes, use Bundle Buggy. See
http://bundlebuggy.aaronbentley.com/help for a link to all the
outstanding merge requests together with an explanation of the columns.
Bundle Buggy will also mail you a link to track just your change.

Of course, the best choice for you will depend on numerous factors:
the number of changes you may be making, the complexity of the changes, etc.
As a starting suggestion though:

create a local copy of the main development branch (bzr.dev) by using
this command:

bzr branch http://bazaar-vcs.org/bzr/bzr.dev/ bzr.dev

keep your copy of bzr.dev prestine (by not developing in it) and keep
it up to date (by using bzr pull)

create a new branch off your local bzr.dev copy for each issue
(bug or feature) you are working on.

This approach makes it easy to go back and make any required changes
after a code review. Resubmitting the change is then simple with no
risk of accidentially including edits related to other issues you may
be working on. After the changes for an issue are accepted and merged,
the associated branch can be deleted or archived as you wish.

Reliability is a critical success factor for any Version Control System.
We want Bazaar to be highly reliable across multiple platforms while
evolving over time to meet the needs of its community.

In a nutshell, this is want we expect and encourage:

New functionality should have test cases. Preferably write the
test before writing the code.

In general, you can test at either the command-line level or the
internal API level. See Writing tests below for more detail.

Try to practice Test-Driven Development: before fixing a bug, write a
test case so that it does not regress. Similarly for adding a new
feature: write a test case for a small version of the new feature before
starting on the code itself. Check the test fails on the old code, then
add the feature or fix and check it passes.

By doing these things, the Bazaar team gets increased confidence that
changes do what they claim to do, whether provided by the core team or
by community members. Equally importantly, we can be surer that changes
down the track do not break new features or bug fixes that you are
contributing today.

As of May 2007, Bazaar ships with a test suite containing over 6000 tests
and growing. We are proud of it and want to remain so. As community
members, we all benefit from it. Would you trust version control on
your project to a product without a test suite like Bazaar has?

In general tests should be placed in a file named test_FOO.py where
FOO is the logical thing under test. That file should be placed in the
tests subdirectory under the package being tested.

For example, tests for merge3 in bzrlib belong in bzrlib/tests/test_merge3.py.
See bzrlib/tests/test_sampler.py for a template test script.

Tests can be written for the UI or for individual areas of the library.
Choose whichever is appropriate: if adding a new command, or a new command
option, then you should be writing a UI test. If you are both adding UI
functionality and library functionality, you will want to write tests for
both the UI and the core behaviours. We call UI tests 'blackbox' tests
and they are found in bzrlib/tests/blackbox/*.py.

When writing blackbox tests please honour the following conventions:

Place the tests for the command 'name' in
bzrlib/tests/blackbox/test_name.py. This makes it easy for developers
to locate the test script for a faulty command.

Use the 'self.run_bzr("name")' utility function to invoke the command
rather than running bzr in a subprocess or invoking the
cmd_object.run() method directly. This is a lot faster than
subprocesses and generates the same logging output as running it in a
subprocess (which invoking the method directly does not).

Only test the one command in a single test script. Use the bzrlib
library when setting up tests and when evaluating the side-effects of
the command. We do this so that the library api has continual pressure
on it to be as functional as the command line in a simple manner, and
to isolate knock-on effects throughout the blackbox test suite when a
command changes its name or signature. Ideally only the tests for a
given command are affected when a given command is changed.

If you have a test which does actually require running bzr in a
subprocess you can use run_bzr_subprocess. By default the spawned
process will not load plugins unless --allow-plugins is supplied.

We make selective use of doctests. In general they should provide
examples within the API documentation which can incidentally be tested. We
don't try to test every important case using doctests -- regular Python
tests are generally a better solution.

In our enhancements to unittest we allow for some addition results beyond
just success or failure.

If a test can't be run, it can say that it's skipped. This is typically
used in parameterized tests - for example if a transport doesn't support
setting permissions, we'll skip the tests that relating to that.

Raising TestSkipped is a good idea when you want to make it clear that the
test was not run, rather than just returning which makes it look as if it
was run and passed.

A subtly different case is a test that should run, but can't run in the
current environment. This covers tests that can only run in particular
operating systems or locales, or that depend on external libraries. Here
we want to inform the user that they didn't get full test coverage, but
they possibly could if they installed more libraries. These are expressed
as a dependency on a feature so we can summarise them, and so that the
test for the feature is done only once. (For historical reasons, as of
May 2007 many cases that should depend on features currently raise
TestSkipped.) The typical use is:

Known failures are when a test exists but we know it currently doesn't
work, allowing the test suite to still pass. These should be used with
care, we don't want a proliferation of quietly broken tests. It might be
appropriate to use them if you've committed a test for a bug but not the
fix for it, or if something works on Unix but not on Windows.

It's important to test handling of errors and exceptions. Because this
code is often not hit in ad-hoc testing it can often have hidden bugs --
it's particularly common to get NameError because the exception code
references a variable that has since been renamed.

In general we want to test errors at two levels:

A test in test_errors.py checking that when the exception object is
constructed with known parameters it produces an expected string form.
This guards against mistakes in writing the format string, or in the
str representations of its parameters. There should be one for
each exception class.

Tests that when an api is called in a particular situation, it raises
an error of the expected class. You should typically use
assertRaises, which in the Bazaar test suite returns the exception
object to allow you to examine its parameters.

In some cases blackbox tests will also want to check error reporting. But
it can be difficult to provoke every error through the commandline
interface, so those tests are only done as needed -- eg in response to a
particular bug or if the error is reported in an unusual way(?) Blackbox
tests should mostly be testing how the command-line interface works, so
should only test errors if there is something particular to the cli in how
they're displayed or handled.

The Transport layer handles access to local or remote directories.
Each Transport object acts like a logical connection to a particular
directory, and it allows various operations on files within it. You can
clone a transport to get a new Transport connected to a subdirectory or
parent directory.

Transports are not used for access to the working tree. At present
working trees are always local and they are accessed through the regular
Python file io mechanisms.

Transports work in URLs. Take note that URLs are by definition only
ASCII - the decision of how to encode a Unicode string into a URL must be
taken at a higher level, typically in the Store. (Note that Stores also
escape filenames which cannot be safely stored on all filesystems, but
this is a different level.)

The main reason for this is that it's not possible to safely roundtrip a
URL into Unicode and then back into the same URL. The URL standard
gives a way to represent non-ASCII bytes in ASCII (as %-escapes), but
doesn't say how those bytes represent non-ASCII characters. (They're not
guaranteed to be UTF-8 -- that is common but doesn't happen everywhere.)

For example if the user enters the url http://example/%e0 there's no
way to tell whether that character represents "latin small letter a with
grave" in iso-8859-1, or "latin small letter r with acute" in iso-8859-2
or malformed UTF-8. So we can't convert their URL to Unicode reliably.

Equally problematic if we're given a url-like string containing non-ascii
characters (such as the accented a) we can't be sure how to convert that
to the correct URL, because we don't know what encoding the server expects
for those characters. (Although this is not totally reliable we might still
accept these and assume they should be put into UTF-8.)

A similar edge case is that the url http://foo/sweet%2Fsour contains
one directory component whose name is "sweet/sour". The escaped slash is
not a directory separator. If we try to convert URLs to regular Unicode
paths this information will be lost.

This implies that Transports must natively deal with URLs; for simplicity
they only deal with URLs and conversion of other strings to URLs is done
elsewhere. Information they return, such as from list_dir, is also in
the form of URL components.

We have a commitment to 6 months API stability - any supported symbol in a
release of bzr MUST NOT be altered in any way that would result in
breaking existing code that uses it. That means that method names,
parameter ordering, parameter names, variable and attribute names etc must
not be changed without leaving a 'deprecated forwarder' behind. This even
applies to modules and classes.

If you wish to change the behaviour of a supported API in an incompatible
way, you need to change its name as well. For instance, if I add an optional keyword
parameter to branch.commit - that's fine. On the other hand, if I add a
keyword parameter to branch.commit which is a required transaction
object, I should rename the API - i.e. to 'branch.commit_transaction'.

When renaming such supported API's, be sure to leave a deprecated_method (or
_function or ...) behind which forwards to the new API. See the
bzrlib.symbol_versioning module for decorators that take care of the
details for you - such as updating the docstring, and issuing a warning
when the old api is used.

For unsupported API's, it does not hurt to follow this discipline, but it's
not required. Minimally though, please try to rename things so that
callers will at least get an AttributeError rather than weird results.

Imports should be done at the top-level of the file, unless there is
a strong reason to have them lazily loaded when a particular
function runs. Import statements have a cost, so try to make sure
they don't run inside hot functions.

Module names should always be given fully-qualified,
i.e. bzrlib.hashcache not just hashcache.

Functions, methods or members that are "private" to bzrlib are given
a leading underscore prefix. Names without a leading underscore are
public not just across modules but to programmers using bzrlib as an
API. As a consequence, a leading underscore is appropriate for names
exposed across modules but that are not to be exposed to bzrlib API
programmers.

We prefer class names to be concatenated capital words (TestCase)
and variables, methods and functions to be lowercase words joined by
underscores (revision_id, get_revision).

For the purposes of naming some names are treated as single compound
words: "filename", "revno".

Consider naming classes as nouns and functions/methods as verbs.

Try to avoid using abbreviations in names, because there can be
inconsistency if other people use the full name.

Python destructors (__del__) work differently to those of other
languages. In particular, bear in mind that destructors may be called
immediately when the object apparently becomes unreferenced, or at some
later time, or possibly never at all. Therefore we have restrictions on
what can be done inside them.

Never use a __del__ method without asking Martin/Robert first.

Never rely on a __del__ method running. If there is code that
must run, do it from a finally block instead.

Never import from inside a __del__ method, or you may crash the
interpreter!!

In some places we raise a warning from the destructor if the object
has not been cleaned up or closed. This is considered OK: the warning
may not catch every case but it's still useful sometimes.

In some places we have variables which point to callables that construct
new instances. That is to say, they can be used a lot like class objects,
but they shouldn't be named like classes:

> I think that things named FooBar should create instances of FooBar when
> called. Its plain confusing for them to do otherwise. When we have
> something that is going to be used as a class - that is, checked for via
> isinstance or other such idioms, them I would call it foo_class, so that
> it is clear that a callable is not sufficient. If it is only used as a
> factory, then yes, foo_factory is what I would use.

Several places in Bazaar use (or will use) a registry, which is a
mapping from names to objects or classes. The registry allows for
loading in registered code only when it's needed, and keeping
associated information such as a help string or description.

To make startup time faster, we use the bzrlib.lazy_import module to
delay importing modules until they are actually used. lazy_import uses
the same syntax as regular python imports. So to import a few modules in a
lazy fashion do:

At this point, all of these exist as a ImportReplacer object, ready to
be imported once a member is accessed. Also, when importing a module into
the local namespace, which is likely to clash with variable names, it is
recommended to prefix it as _mod_<module>. This makes it clearer that
the variable is a module, and these object should be hidden anyway, since
they shouldn't be imported into other namespaces.

While it is possible for lazy_import() to import members of a module
when using the frommoduleimportmember syntax, it is recommended to
only use that syntax to load sub modules frommoduleimportsubmodule.
This is because variables and classes can frequently be used without
needing a sub-member for example:

It also is incorrect to assign ImportReplacer objects to other variables.
Because the replacer only knows about the original name, it is unable to
replace other variables. The ImportReplacer class will raise an
IllegalUseOfScopeReplacer exception if it can figure out that this
happened. But it requires accessing a member more than once from the new
variable, so some bugs are not detected right away.

The null revision is the ancestor of all revisions. Its revno is 0, its
revision-id is null:, and its tree is the empty tree. When referring
to the null revision, please use bzrlib.revision.NULL_REVISION. Old
code sometimes uses None for the null revision, but this practice is
being phased out.

There are some common requirements in the library: some parameters need to be
unicode safe, some need byte strings, and so on. At the moment we have
only codified one specific pattern: Parameters that need to be unicode
should be checked via bzrlib.osutils.safe_unicode. This will coerce the
input into unicode in a consistent fashion, allowing trivial strings to be
used for programmer convenience, but not performing unpredictably in the
presence of different locales.

(The strategy described here is what we want to get to, but it's not
consistently followed in the code at the moment.)

bzrlib is intended to be a generically reusable library. It shouldn't
write messages to stdout or stderr, because some programs that use it
might want to display that information through a GUI or some other
mechanism.

We can distinguish two types of output from the library:

Structured data representing the progress or result of an
operation. For example, for a commit command this will be a list
of the modified files and the finally committed revision number
and id.

These should be exposed either through the return code or by calls
to a callback parameter.

A special case of this is progress indicators for long-lived
operations, where the caller should pass a ProgressBar object.

Unstructured log/debug messages, mostly for the benefit of the
developers or users trying to debug problems. This should always
be sent through bzrlib.trace and Python logging, so that
it can be redirected by the client.

The distinction between the two is a bit subjective, but in general if
there is any chance that a library would want to see something as
structured data, we should make it so.

The policy about how output is presented in the text-mode client
should be only in the command-line tool.

In general tests should be placed in a file named test_FOO.py where
FOO is the logical thing under test. That file should be placed in the
tests subdirectory under the package being tested.

For example, tests for merge3 in bzrlib belong in bzrlib/tests/test_merge3.py.
See bzrlib/tests/test_sampler.py for a template test script.

Tests can be written for the UI or for individual areas of the library.
Choose whichever is appropriate: if adding a new command, or a new command
option, then you should be writing a UI test. If you are both adding UI
functionality and library functionality, you will want to write tests for
both the UI and the core behaviours. We call UI tests 'blackbox' tests
and they are found in bzrlib/tests/blackbox/*.py.

When writing blackbox tests please honour the following conventions:

Place the tests for the command 'name' in
bzrlib/tests/blackbox/test_name.py. This makes it easy for developers
to locate the test script for a faulty command.

Use the 'self.run_bzr("name")' utility function to invoke the command
rather than running bzr in a subprocess or invoking the
cmd_object.run() method directly. This is a lot faster than
subprocesses and generates the same logging output as running it in a
subprocess (which invoking the method directly does not).

Only test the one command in a single test script. Use the bzrlib
library when setting up tests and when evaluating the side-effects of
the command. We do this so that the library api has continual pressure
on it to be as functional as the command line in a simple manner, and
to isolate knock-on effects throughout the blackbox test suite when a
command changes its name or signature. Ideally only the tests for a
given command are affected when a given command is changed.

If you have a test which does actually require running bzr in a
subprocess you can use run_bzr_subprocess. By default the spawned
process will not load plugins unless --allow-plugins is supplied.

We make selective use of doctests. In general they should provide
examples within the API documentation which can incidentally be tested. We
don't try to test every important case using doctests -- regular Python
tests are generally a better solution.

Commands should return non-zero when they encounter circumstances that
the user should really pay attention to - which includes trivial shell
pipelines.

Recommended values are:

OK.

Conflicts in merge-like operations, or changes are present in
diff-like operations.

Unrepresentable diff changes (i.e. binary files that we cannot show
a diff of).

An error or exception has occurred.

Errors are handled through Python exceptions. Exceptions should be defined
inside bzrlib.errors, so that we can see the whole tree at a glance.

We broadly classify errors as either being either internal or not,
depending on whether internal_error is set or not. If we think it's our
fault, we show a backtrace, an invitation to report the bug, and possibly
other details. This is the default for errors that aren't specifically
recognized as being caused by a user error. Otherwise we show a briefer
message, unless -Derror was given.

Many errors originate as "environmental errors" which are raised by Python
or builtin libraries -- for example IOError. These are treated as being
our fault, unless they're caught in a particular tight scope where we know
that they indicate a user errors. For example if the repository format
is not found, the user probably gave the wrong path or URL. But if one of
the files inside the repository is not found, then it's our fault --
either there's a bug in bzr, or something complicated has gone wrong in
the environment that means one internal file was deleted.

Many errors are defined in bzrlib/errors.py but it's OK for new errors
to be added near the place where they are used.

Exceptions are formatted for the user by conversion to a string
(eventually calling their __str__ method.) As a convenience the
._fmt member can be used as a template which will be mapped to the
error's instance dict.

New exception classes should be defined when callers might want to catch
that exception specifically, or when it needs a substantially different
format string.

Exception strings should start with a capital letter and should not have a
final fullstop. If long, they may contain newlines to break the text.

When you change bzrlib, please update the relevant documentation for the
change you made: Changes to commands should update their help, and
possibly end user tutorials; changes to the core library should be
reflected in API documentation.

If you make a user-visible change, please add a note to the NEWS file.
The description should be written to make sense to someone who's just
a user of bzr, not a developer: new functions or classes shouldn't be
mentioned, but new commands, changes in behaviour or fixed nontrivial
bugs should be listed. See the existing entries for an idea of what
should be done.

Within each release, entries in the news file should have the most
user-visible changes first. So the order should be approximately:

changes to existing behaviour - the highest priority because the
user's existing knowledge is incorrect

new features - should be brought to their attention

bug fixes - may be of interest if the bug was affecting them, and
should include the bug number if any

major documentation changes

changes to internal interfaces

People who made significant contributions to each change are listed in
parenthesis. This can include reporting bugs (particularly with good
details or reproduction recipes), submitting patches, etc.

The docstring of a command is used by bzrhelp to generate help output
for the command. The list 'takes_options' attribute on a command is used by
bzrhelp to document the options for the command - the command
docstring does not need to document them. Finally, the '_see_also'
attribute on a command can be used to reference other related help topics.

The copyright policy for bzr was recently made clear in this email (edited
for grammatical correctness):

The attached patch cleans up the copyright and license statements in
the bzr source. It also adds tests to help us remember to add them
with the correct text.
We had the problem that lots of our files were "Copyright Canonical
Development Ltd" which is not a real company, and some other variations
on this theme. Also, some files were missing the GPL statements.
I want to be clear about the intent of this patch, since copyright can
be a little controversial.
1) The big motivation for this is not to shut out the community, but
just to clean up all of the invalid copyright statements.
2) It has been the general policy for bzr that we want a single
copyright holder for all of the core code. This is following the model
set by the FSF, which makes it easier to update the code to a new
license in case problems are encountered. (For example, if we want to
upgrade the project universally to GPL v3 it is much simpler if there is
a single copyright holder). It also makes it clearer if copyright is
ever debated, there is a single holder, which makes it easier to defend
in court, etc. (I think the FSF position is that if you assign them
copyright, they can defend it in court rather than you needing to, and
I'm sure Canonical would do the same).
As such, Canonical has requested copyright assignments from all of the
major contributers.
3) If someone wants to add code and not attribute it to Canonical, there
is a specific list of files that are excluded from this check. And the
test failure indicates where that is, and how to update it.
4) If anyone feels that I changed a copyright statement incorrectly, just
let me know, and I'll be happy to correct it. Whenever you have large
mechanical changes like this, it is possible to make some mistakes.
Just to reiterate, this is a community project, and it is meant to stay
that way. Core bzr code is copyright Canonical for legal reasons, and
the tests are just there to help us maintain that.

Bazaar has a few facilities to help debug problems by going into pdb, the
Python debugger.

If the BZR_PDB environment variable is set
then bzr will go into pdb post-mortem mode when an unhandled exception
occurs.

If you send a SIGQUIT signal to bzr, which can be done by pressing
Ctrl-\ on Unix, bzr will go into the debugger immediately. You can
continue execution by typing c. This can be disabled if necessary
by setting the environment variable BZR_SIGQUIT_PDB=0.

When a Command object is created, it is given a member variable
accessible by self.outf. This is a file-like object, which is bound to
sys.stdout, and should be used to write information to the screen,
rather than directly writing to sys.stdout or calling print.
This file has the ability to translate Unicode objects into the correct
representation, based on the console encoding. Also, the class attribute
encoding_type will effect how unprintable characters will be
handled. This parameter can take one of 3 values:

replace

Unprintable characters will be represented with a suitable replacement
marker (typically '?'), and no exception will be raised. This is for
any command which generates text for the user to review, rather than
for automated processing.
For example: bzrlog should not fail if one of the entries has text
that cannot be displayed.

strict

Attempting to print an unprintable character will cause a UnicodeError.
This is for commands that are intended more as scripting support, rather
than plain user review.
For exampl: bzrls is designed to be used with shell scripting. One
use would be bzrls--null--unknows|xargs-0rm. If bzr
printed a filename with a '?', the wrong file could be deleted. (At the
very least, the correct file would not be deleted). An error is used to
indicate that the requested action could not be performed.

exact

Do not attempt to automatically convert Unicode strings. This is used
for commands that must handle conversion themselves.
For example: bzrdiff needs to translate Unicode paths, but should
not change the exact text of the contents of the files.

Because Transports work in URLs (as defined earlier), printing the raw URL
to the user is usually less than optimal. Characters outside the standard
set are printed as escapes, rather than the real character, and local
paths would be printed as file:// urls. The function
unescape_for_display attempts to unescape a URL, such that anything
that cannot be printed in the current encoding stays an escaped URL, but
valid characters are generated where possible.

We write some extensions in C using pyrex. We design these to work in
three scenarios:

User with no C compiler

User with C compiler

Developers

The recommended way to install bzr is to have a C compiler so that the
extensions can be built, but if no C compiler is present, the pure python
versions we supply will work, though more slowly.

For developers we recommend that pyrex be installed, so that the C
extensions can be changed if needed.

For the C extensions, the extension module should always match the
original python one in all respects (modulo speed). This should be
maintained over time.

To create an extension, add rules to setup.py for building it with pyrex,
and with distutils. Now start with an empty .pyx file. At the top add
"include 'yourmodule.py'". This will import the contents of foo.py into this
file at build time - remember that only one module will be loaded at
runtime. Now you can subclass classes, or replace functions, and only your
changes need to be present in the .pyx file.

Note that pyrex does not support all 2.4 programming idioms, so some
syntax changes may be required. I.e.

'from foo import (bar, gam)' needs to change to not use the brackets.

'import foo.bar as bar' needs to be 'import foo.bar; bar = foo.bar'

If the changes are too dramatic, consider
maintaining the python code twice - once in the .pyx, and once in the .py,
and no longer including the .py file.